Screening

Screening, in general, is the investigation of a great number of something (for instance, people) looking for those with a particular problem or feature. One example is at an airport, where many bags get x-rayed to try to detect any which may contain weapons or explosives. People are also screened going through a metal detector. Even though the procedure aims at a large number of screens, it is always equivalent to sampling in statistics, because the complete population is almost always inaccessible for screening.